My name is Wei Shao, I just a beginner of Freesurfer. As I play around with the tutorial data, here is a problem I met, I tried to recon-all the dicoms data as the tutorial instruction practice with the date instructed, but it always reports like the SUBJECTS_DIR directory does not exist. 

[shao@WeiS ~]$ export TUTORIAL_DATA=tutorial_data
[shao@WeiS ~]$ export SUBJECTS_DIR=$TUTORIAL_DATA/practice_with_data
[shao@WeiS ~]$ cd $SUBJECTS_DIR/dicoms
[shao@WeiS dicoms]$ recon-all -all -i I50 -s  Subj001
ERROR: SUBJECTS_DIR tutorial_data/practice_with_data does not exist.
[shao@WeiS dicoms]$ source $FREESURFER_HOME/SetUpFreeSurfer.sh
-------- freesurfer-linux-centos7_x86_64-7.1.0-20200511-813297b --------
Setting up environment for FreeSurfer/FS-FAST (and FSL)
WARNING: tutorial_data/practice_with_data does not exist
FREESURFER_HOME   /usr/local/freesurfer/7.1.0-1
FSFAST_HOME       /usr/local/freesurfer/7.1.0-1/fsfast
FSF_OUTPUT_FORMAT nii.gz
SUBJECTS_DIR      tutorial_data/practice_with_data
MNI_DIR           /usr/local/freesurfer/7.1.0-1/mni
[shao@WeiS dicoms]$ pwd
/home/shao/tutorial_data/practice_with_data/dicoms
[shao@WeiS dicoms]$

What I should do to fix this problem, Thanks in advance.

Best,

Wei